None of the other node.js RSS modules that I could find supported the flexibility that I wanted or were too slow. Additionally, many of them seemed overly complex when all we're doing here is building a RSS feed. Not rocket science.

node-rss uses the libxmljs library to construct the actual feed.
Unfortunately, some of the features of the library that are needed are only available in the current master branch. You will need to download the libxmljs source, compile, and install it yourself. Fortunately, this is fairly straight forward. https://github.com/polotek/libxmljs/

You will also need to have the libxml2 AND libxml2-dev packages installed on your system.